In our previous article we discussed the building understanding of the contribution of the hamstrings in the production of horizontal forces during acceleration and running tasks. And as we mentioned we have been using this understanding to assess hamstring injuries across multiple tasks, directions of movement and velocities.
With this in mind the biggest factor that has become apparent when assessing athletes as they come back from hamstring injuries is that they often have deficits in particularly planes of movement and at different velocities of contraction. And this can make the process confusing if you are not assessing these features.
To give you an example we had a track and field athlete with a grade two biceps femoris injury. The rehabilitation process initially was progressing well and the athlete was able to return to running training at reduced but gradually increasing intensities. However once the athlete started to run at greater than 80% they experienced the same feeling repeatedly. As they started to run faster their was a tightness, pulling and fatigue feeling creeping in each time.
We decided that we should reassess the current capabilities of the athlete. To put it in context the athlete had been exposed to loaded strength training for the hamstring at both short and longer lengths, with exercises classified as more knee dominant (such as bridge tasks and Nordic hamstring loading) as well as hip dominant tasks such as good mornings, hip thrusts and Romanian deadlifts. The rehabilitation had also included the introduction of running based drills and variations before returning to running at increasing speeds.
Upon assessment however it became clear. The athlete was strong in this injured hamstring in fact in both short and long lever hamstring loading the injured side was able to produce the same if not more force. But what became extremely evident was that the RFD (rate of force development) that is the speed at which such forces are able to be applied was significantly reduced in the long lever tasks.
Why was this important?
Well as highlighted by the previous article the contribution of the hamstring to the ability to produce horizontal forces (typically at longer lengths) is vital to the ability to produce horizontal momentum changes, i.e accelerate to high top speeds. What we were seeing was the missing piece to why the athlete could run relatively fast, but when the speed started to shift beyond 80% the hamstring was giving signs that it was not tolerating the combination of high velocity contractions at longer lengths.
Based off this information we began implementing a series of hamstring exercises that complemented these qualities. They were tasks that included high speed, long lever contractions and also the ability to tolerate high speed braking forces at such speed. This period of rehabilitation included resistance exercises at high speed such as high velocity single leg good mornings, ballistic hamstring bridge catches as increasing lengths and the inclusion of high speed running drills that emphasized horizontal force application, in hip dominant, longer length movements such as bent and straight leg scissor drills.
After implementing these tasks over the course of 7-10 days, the athlete reported that the shackles were released and the ability to run at speeds faster than 80% became comfortable. Upon retesting of the hamstring function the rate of force development at longer lengths closed to become symmetrical over a two week period. At such time the athlete was able and willing to resume training at full intensity. This experienced highlighted that there is a need to address loading across the spectrum from low force and lower velocities to high force and high velocities and from the entire spectrum of hamstring lengths from short knee dominant to long hip dominant exercises. Without addressing this entire spectrum the ability for the hamstring to produce forces required for fast movements such as high speed running is compromised.
Take away tips for hamstring rehabilitation.
- Assess hamstring function across the spectrum from short to long lengths and from low to high velocities under high force application tasks.
- Use this information to address loading progressively across this spectrum to give athletes the capabilities across this spectrum.
- Progressively introduce and overload tasks that mimic the requirements of high speed running that they need, high velocity, long lever, horizontal projection tasks.